A5108067906- Adaptive optics and wavefront sensing
- Optical Systems and Laser Technology
- Advanced optical system design
- Iterative Learning Control Systems
- Hydraulic and Pneumatic Systems
- Educational Technology and Assessment
- Video Analysis and Summarization
- Astronomy and Astrophysical Research
- Vehicle License Plate Recognition
- Laser Material Processing Techniques
- Control Systems in Engineering
- Handwritten Text Recognition Techniques
- Infrared Target Detection Methodologies
- Speech and dialogue systems
Institute of Optics and Electronics, Chinese Academy of Sciences
2010-2024
University of Chinese Academy of Sciences
2023-2024
Chinese Academy of Sciences
2010-2024
Institute of Automation
2023
Institute of Acoustics
2012
The precise secondary mirror alignment is a key factor to ensure the imaging quality of segmented telescope with high resolution demand. In this paper, two-step method using an improved stochastic parallel gradient descent (SPGD) algorithm called Nadam SPGD proposed. Simulation results show that our can distinguish aberrations caused by phase errors primary and position precisely, align quickly accurately. enhance correction efficiency more than two times compared traditional algorithm.
We propose using a piezoelectric adaptive secondary mirror (PASM) in the medium-sized telescopes with 2-4 m aperture for structure and control simplification by utilizing actuators contrast voice-coil mirror. A closed-loop experimental setup was built on-sky demonstration of 73-element PASM developed our laboratory. In this Letter, optics system are introduced. High-resolution stellar images were obtained to correct high-order wavefront errors May 2016. To best knowledge, is first successful...
A low frequency wavefront aberration correction method for solar telescopes based on secondary mirror movement is proposed to correct dynamic during the operation of telescope. The ability this analyzed and validated by numerical simulation experiments. Theoretical analysis both indicate system processes significant given 10 times higher than frequency. After spatiotemporal division actual data from telescope, experiment result proves that can effectively reduce overall RMS aberrations with...
To satisfy the demands of high image quality and resolutions, telescope alignment is indispensable. In this paper, a wavefront sensorless method based on modified stochastic parallel gradient descent algorithm (SPGD) called adaptive moment estimation SPGD (Adam SPGD) proposed. Simulations are carried out using four-mirror telescope, whose aperture 6 m fields view Φ2°. Three misalignments shown as examples. Positions secondary mirror third employed to compensate aberrations. The results show...
The model for differential power screw transmission is established, and the mathematical expression of stick-slip motion derived based on friction, in addition, influences parameters are analyzed qualitatively. Based dynamical equations analysis, precision stability designed actuator obtained, result compared to it with software SIMULINK verify.
To acquire images with higher accuracy of wide-field telescopes, deformable mirrors more than 100 actuators are used, making the telescope alignment complex and time-consuming. Furthermore, position obscuration caused by secondary mirror in experiment system is changed difference fields view, response matrix different various view. solve this problem, transfer functions corresponding to view calculated according wavefront edge check boundary conditions. In paper, a model-based method...
Existing video text detection methods mostly track texts with appearance feature only, thus are easily influenced by the change of perspective and illumination. In this paper, we propose an end-to-end detector that tracks based on robust representation fusing multiple descriptors. First, introduce a character center segmentation branch to extract semantic feature, which encodes category position information characters. And for extracting topology each instance, relative awareness encode...
Active optics is one of the key technologies for constructing modern large telescope. It's necessary to study performance an active system theoretically in advance. In this paper we built a 1.2 m thin-mirror model with 36 axial supports and 3 lateral supports. order ensure select appropriate force actuators, carried out following analyses through FEA: ability duplicate first 15 Zernike modes natural resonance modes; mirror deformations before after corrections under gravitational loads;...
Based on the analysis of a 1.2m-diameter active primary mirror system under gravity load, several performance parameters actuator are reported in this paper. The is demanded to satisfy optics correction, support axial load mirror, and compensate deformation supports. quasi-Zernike polynomials employed fit maximal allowed surface error telescope compute force accuracy actuator. Moreover, analyzed by using finite element (FE) method. Through above procedures, parameters, such as range,...